Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Fondaparinux

Fondaparinux

Synthetic factor Xa inhibitor (pentasaccharide)

VTEProphylaxisSCAdult

Indication

Hip fracture/replacement prophylaxis β€’ Acute VTE (selected) when heparin unsuitable

At a glance

INDICATIONS (CORE USE)

VTE prophylaxis (orthopedic/medical) and treatment β€” **CrCl <30 contraindicated for prophylaxis** per most labels; **no protamine reversal**.

ADULT DOSE (STANDARD)

2.5 mg SC daily prophylaxis; treatment **5–10 mg daily** weight-based β€” verify label

MAX DOSE

10 mg daily treatment cap in labeling for highest weight band

Route

SC

PEDIATRIC DOSE

Not standard

Do not miss

Must-not-miss safety points

Major warning

- **No reversal agent** β€” major bleed = supportive + PCC only in desperate protocols + hematology - Renal elimination β€” **avoid CrCl <30** for prophylaxis - HIT history: may use fondaparinux when heparins contraindicated (context β€” specialist)

Indications

USE IF: Prophylaxis when renal function adequate; HIT treatment alternative sometimes. AVOID IF: CrCl <30 for prophylaxis, severe active bleeding, weight <50 kg for some doses.

Primary

  • Major orthopedic surgery thromboprophylaxis
  • Acute superficial vein thrombosis (some regions)
  • VTE treatment when heparin contraindicated (selected)

Secondary

  • HIT thrombosis treatment pathway (non-heparin option)

Dosing

STANDARD (ADULT PO)

2.5 mg SC daily for prophylaxis in approved surgeries

ADULT DOSE

Treatment doses **5, 7.5, 10 mg** SC daily by weight β€” label table. CrCl **30–50:** caution; **<30** prophylaxis contraindicated. Duration matches orthopedic guideline (often 10–35 days).

PEDIATRIC DOSE

N/A.

MAX DOSE

10 mg daily treatment.

Practical Note

Do not mix with LMWH interchangeably β€” different monitoring and reversal.

Warnings

Clinical warnings

  • **No reliable reversal** β€” protamine is **ineffective**; major bleed β†’ early **hematology**, massive transfusion protocol, **PCC only if protocol allows**
  • Long duration of effect β€” anticipate **prolonged anticoagulation** after last dose when planning procedures
  • Neuraxial anesthesia timing
  • Bacterial endocarditis caution

Adverse effects

  • Bleeding
  • anemia
  • thrombocytopenia (rare)
  • injection site reaction

Contraindications

  • **Active pathological / major bleeding** β€” stabilize/reverse per protocol before routine (re)start unless embedded in explicit reversal plan
  • **Upcoming invasive procedure** β€” **do not continue blindly**; document **hold/bridge/switch** with anesthesia/surgery when applicable
  • **Severe renal failure** where label contraindicates β€” **accumulation** + **no reversal**
  • Severe renal impairment for prophylaxis (CrCl <30)
  • Active major bleeding
  • Body weight <50 kg for prophylaxis (label)

Drug interactions

  • **NSAID, antiplatelet, or SSRI added** β†’ **bleeding risk ↑** β†’ **reassess stack** and procedure timing
  • **Renal decline** on renally cleared agent β†’ **dose/hold** per CrCl + pharmacy
  • **Nephrotoxin or AKI** β†’ **reassess renal** + remember **long offset (~17h TΒ½)** before any procedure
  • Other anticoagulants
  • antiplatelets

Special populations

Pediatrics

Not standard

Pregnancy

Limited β€” specialist; LMWH often preferred.

Lactation

See lactation references and product labeling.

Renal impairment

Severe renal impairment β†’ drug accumulation β€” contraindicated or dose avoided. **CrCl scaffold (FMBM β€” titrate to FDA/SFDA label + pharmacy / anticoagulation clinic):** - **CrCl β‰₯50** β†’ **2.5 mg daily** prophylaxis (orthopedic) or weight-tier **5–10 mg** treatment per label - **CrCl 10–50** β†’ **30–50** band: use caution; **<30** β†’ **prophylaxis contraindicated** (US/EU labels); treatment only with **hematology** + bleed plan (**no antidote**) - **CrCl <10** β†’ **avoid** β€” drug accumulates (**~17 h TΒ½**); procedures and neuraxial planning must assume **prolonged effect**

Hepatic impairment

Mild-moderate β€” limited data; severe β€” caution.

Elderly

Renal function assessment mandatory.

Administration

SC; rotate sites; fixed doses by weight band for treatment.

Monitoring

  • Monitor: - **What to check + when:** **CrCl** baseline + with illness; **Hgb** if bleed suspected β€” **no reliable reversal** - **Escalation β€” major bleed:** **Hematology** + supportive; **PCC** only explicit protocol - **Escalation β€” elective surgery:** Plan **days ahead** (long TΒ½); neuraxial often **avoid / prolonged hold** - **Starting warfarin for acute VTE** β†’ **parenteral overlap** when indicated β€” **do not stop parenteral prematurely** per guideline - **Low-risk AF elective surgery** β†’ **avoid routine bridging** β€” use thromboembolic risk stratification - Renal function baseline - Clinical bleed surveillance β€” no routine anti-Xa for fondaparinux standardly
  • Recheck: - **Escalation β€” CrCl <30:** Prophylaxis often **contraindicated** β€” reassess exposure - **Procedure or neuraxial in 48–72h** β†’ **reassess anticoagulant plan** β€” DOAC hold windows **β‰ ** warfarin; document last dose time - **Interacting drug added or stopped** β†’ **recheck INR (warfarin) or reassess bleed risk / renal (DOAC)** within **48–72h** - If targets not met after reassessment of dose, organ function, and interactions β†’ escalate per protocol (DO NOT continue blindly)
  • Hold if:
    - **Bleeding, unexplained Hb drop, thunderclap headache, or focal neuro signs** β†’ **hold** anticoagulant + escalate per bleed protocol

Overdose / toxicity

Clinical Picture

β€’ **No bleed:** Hold if renal failure / pre-op β€” long offset β€’ **Minor bleed:** Hold β†’ supportive β€” **protamine ineffective** β€’ **Major bleed:** Stop β†’ **hematology** + MTP + **PCC** only if explicit protocol + **ICU**

Immediate Actions

β€’ **No bleed:** Hold β†’ assess renal + procedure timing β€’ **Minor bleed:** Local measures + transfuse if anemic β€’ **Major bleed:** Supportive β†’ **hematology early**; PCC/rFVIIa only per desperate policy β†’ **ICU**

Antidote

**No specific antidote** β€” stop drug/supportive care; **major bleed** β†’ institutional reversal pathway; anaphylaxis β†’ **epinephrine** per ACLS

Decontamination

β€’ **SC:** N/A

Escalation

β€’ **Major:** **ICU**; **HD** consult (limited clearance)

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield Summary

**Long half-life** β€” plan procedures early. β†’ **No protamine**. β†’ **Renal** rules strict for prophylaxis.

Clinical pearls

Useful in **HIT** treatment pathways when experience available β€” not resident improvisation. *Anticoagulation (all agents):* **A/B/C bleed tiers** β€” no bleed (hold/adjust) vs minor (hold/protocol) vs major (reversal + ICU/heme). **Warfarin:** high INR without bleed **β‰ ** major-bleed pathway; **PCC + IV K** for life-threatening bleed. **Bridging:** warfarin **slow on/off**; **parenteral overlap** when indicated for acute VTE; **no routine bridge** low-risk AF; **DOAC↔warfarin** table-specific. **Neuraxial:** explicit **last-dose β†’ procedure** documentation. Never extend therapy without indication review.

Anticoagulant safety

  • No reversal
  • Renal cutoff
  • Weight bands

Pharmacokinetics

SC bioavailability 100%; renal elimination; TΒ½ ~17 h β€” long duration vs LMWH.

Mechanism of action

Selective antithrombin-mediated factor Xa inhibition (no thrombin inhibition).

Common brand names

Saudi Arabia

Arixtra

Global

(placeholder β€” verify local prefilled syringe / vial)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Reversal agents (PCC, andexanet, idarucizumab) availability and dosing vary by hospital β€” follow local protocol.
  • Perioperative interruption and bridging are **indication-specific** β€” do not copy warfarin rules onto DOACs blindly.
  • Switching between anticoagulants requires manufacturer tables + pharmacy to avoid under- or over-anticoagulation.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • CHEST / ACCP antithrombotic guidance (indication-specific)
  • ESC / AHA stroke and anticoagulation guidelines where applicable
  • ASH β€” HIT and VTE resources
  • FDA / SFDA product labeling
  • Institutional anticoagulation service / formulary
  • CHEST / ACCP antithrombotic guidance (indication-specific)
  • ESC / AHA stroke and anticoagulation guidelines where applicable
  • ASH β€” HIT and VTE resources
  • FDA / SFDA product labeling
  • Institutional anticoagulation service / formulary

Do not miss

  • Document indication, target intensity, and planned duration in the chart
  • Reassess renal/hepatic function after AKI, dehydration, or new interacting medications
  • **No antidote:** Major bleed β†’ **hematology early**; supportive care; **no protamine**.
  • **Renal:** CrCl <30 prophylaxis **contraindicated** β€” accumulation; long **TΒ½** extends risk days.
  • **Neuraxial:** Often **avoid** or extended hold β€” align with **ASRA / anesthesia**.
  • **Do not confuse** with reversible agents β€” surgical planning must start **early**.
  • Using fondaparinux in **CrCl <30** prophylaxis β†’ label violation / bleed risk.
  • Major bleed β†’ call hematology early.
  • **Bridging & transitions (factory scaffold):**
  • **Warfarin** has **delayed onset/offset** β€” do not expect immediate effect or rapid washout like DOACs.
  • **Acute thrombosis** may require **parenteral overlap** when starting/overlapping warfarin or per label β€” **indication-specific**.
  • **Low-risk AF peri-procedure:** **do NOT routinely bridge** β€” stratify thromboembolic risk per guideline/CHEST-style tables.
  • **DOAC ↔ warfarin** switches are **indication- and table-specific** β€” pharmacy + label (valve, APS, renal).
  • **Neuraxial / high-bleed procedure:** document **last dose**, **ASRA/institutional** windows, **restart** only when hemostasis secure.
  • No reversal
  • Renal cutoff
  • Weight bands